Project 2000 Nissan Maxima Part 3 - Throttle In A Bottle -

Project Maxima has continued to tickle the senses as it has evolved into a competent cruiser. Since last appearing in the magazine, the car has been reshod and armed with more power.

We wanted to see how the Nissan would look with mesh wheels and elected to bolt on a set of 18-inch Volk IIIs and grippy Yokohama rubber. The 19-inch AV3s pack far more visual impact, but we were interested to see how 18s looked. The results were impressive and the Maxima still turns heads. In fact, we were followed home and asked about the car on two occasions while rolling the 18s. On tight freeway on-ramps, we pushed the limit of the suspension, often forgetting there were two doors behind us. The Maxima tracks corners so well that it's more coupe than four-door family car.

We are delighted to hear that, based on feedback generated by Project Maxima, HKS is moving to full production on its 2000 Maxima exhaust system. Our prototype system was used to develop the production set-up, which is slated to be on the street by the time this issue hits the newsstands.

It is time to increase the power of the VQ30DE; we thought we'd start with the basic air filter and graduate to something a bit harder hitting. We have often wondered: How good can a replacement-style filter really be? We contacted K&N and took delivery of its drop-in replacement filter for the 2000 Maxima. We then decided to put the Maxima on a muscle-building program that included a dose of nitrous oxide. Nitrous is a great power adder, especially for cars on the fringes of the performance scene that don't have staged performance programs like Hondas and Diamond Stars.

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| Chart 1: The Maxima was dyno'd prior to installation of the air filter or activation of the nitrous kit. This run (made with the HKS exhaust) would serve as a baseline for the other components. The car put down 190.2 hp, which is less than the previous run made in the same trim. The most likely cause of this is the switch to bigger, heavier wheels, which require more energy to turn.

For our throttle in a bottle, we went with ZEX because of its easy-to-install design. The key is the integrated design of the system's distribution block. On one side of the block, there are three wires, a power wire, ground wire and the activation wire that leads to the Throttle Position Sensor (TPS). There is also a port for incoming nitrous that connects to the bottle. On the other side of the block are ports labeled Intake, Regulator and Nozzle. The Regulator port is joined to the fuel pressure regulator to ensure a bump in pressure when the system comes online, while the Intake port ensures that any excess pressure, in case of a spike, is bled off and routed into the intake system so when the throttle plate is closed, fuel pressure returns to stock levels. The Nozzle port funnels the nitrous to the engine. The nozzle itself is fitted with jets that determine the amount of nitrous oxide introduced to the combustion chamber and, consequently, the amount of power that the system will generate.

We employed KG Precision Engineering to handle the installation. Popping the hood, the Maxima looked to be a tough nut to crack because of its crowded engine bay. Hondas have a grip of space on the firewall to mount ignition boxes, relays or the ZEX distribution block. A creative place was found and the block was secured. Grafting the power wire into the mix and securing the ground wire was simple. The only real hurdle we faced was the TPS. The ZEX solenoid must see 4.5 volts from the TPS before it will fire. The Maxima's TPS generated only 3.98 volts at WOT when first wired to the system. Using the TPS adjustment screws, the KG crew was able to realign the TPS so it would generate the proper voltage.

We elected to play it safe and run the smallest jet in the lot-a .38. The ZEX kit can be configured to deliver up to 75 hp while using the stock fuel system. Even considering KG's vast experience with nitrous systems, the install was swift. In about an hour, the Maxima was ready to laugh and we were off to XS Engineering for some dyno pulls. We retested the baseline of the Nissan with the HKS exhaust and netted 190.2 hp and 179.6 lbs-ft of torque. This was a bit less power than before. The only reasons we can come up with for this discrepancy are the wheels. The Volk IIIs are bigger and therefore heavier than the stockers and require more kinetic energy to turn, hence the lower power figures.

When installing the K&N filter, we were shocked to see how much dirt was on the OE element. A 2-minute swap later, the rollers were spinning and the Maxima laid down 194.2 hp. One hundred twenty seconds is a darn fast way to gain 4 hp at the wheels. We decided to make a pull with no filter and the V6 made 194.6; we were impressed with a filter that flowed .4 hp less than an open intake.

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| These jets are the determining factors concerning the power production of the nitrous system. The jets are sized by orifice diameter and we elected to go with the smallest jet-.38

Next up was the funny fog. After a proper cooling down period, the XS Engineering Dynojet was once again brought to life. On the bottle, the Maxima generated 220.1 hp. The graph seemed a bit choppy and we surmised that a fresh set of plugs would smooth the graph and maybe add a pony or two. We were hoping for more power from the kit and KG's Kurt Gordon was quick to point to the fuel pump, not the kit, as the likely culprit. In Kurt's experience, Nissan fuel pumps max out at 60 psi, while others, like Hondas, flow willingly to 80 psi and beyond. We contemplated adding a Kenne Bell Boost-A-Pump, but logistics and scheduling kept us from venturing down that road.

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| When mounting the nitrous bottle, be it in the trunk or within the car, it is wise to face the valve of the bottle toward the front of the car.

On the road, the Maxima felt like it had a gust of extra wind in its sails when the nitrous system was activated. While not a racer by any stretch, when on the bottle, the car passed traffic briskly; the V6 proved to have an appetite for nitrous. Our next installment of Project Maxima will wrap up the series of articles, as we plan to outline some of the other, more extreme, possibilities for power hungry Maxima pilots. Stay tuned.